Attachment for grinding split points on drills



Dec. 12, 1967 R. E. YOUNG 3,

" ATTACHMENT FOR GRINDING'SPLIT POINTS 0N mums Filed March 15, 1965 .4 Sheets-Sheeti I A/VA TOL 1 veaier/ 6' )21/7 R. E. YOUNG Dec. 12, 1967 ATTACHMENT FOR GRINDING SPLIT POINTS ON DRILLS 4 Sheets-Sheet 2 Filed March 15, 1965 II F R. E. YOUNG Dec. 12, 1967 ATTACHMENT FOR GRINDING SPLIT POINTS ON DRILLS 4 Sheets-Sheet Filed March 15, 1965 Dec. 12, 1967 R. E YOUNG ,1

ATTACHMENT FOR GRINDING SPLIT POINTS ON DRILLS Filed March 15, 1965 4 Sheets-Sheet 4,

I wwzym views, respectively, of a drill on which a to Northrop Calif., a corporation of This invention relates to improvements in drill sharpening or pointing equipment and more particularly to modifications in presently known drill pointing machines enabling such machines to perform drill point splitting operations as well as drill pointing operations.

For reasons that are well known, pointing of drills in a conventional manner results in materially increasing the extent (length) of the drills chisel edge. Increasing the length of a drills chisel edge results in reducing the 'cutting 'efiiciency of the drill. Accordingly, if the cutting qualities of a drill are to be maintained at maximum efficiency the length of a drills chisel edge must be reduced each time the drill is sharpened, the foregoing may be accomplished in various Ways. In the present disclosure the subject operation is performed by thinning the web of the drill, specifically by an operation referred to as point splitting. An attachment is disclosed herein adapted to be added to or fabricated integrally with a presently known drill pointing machine whereby point splitting operations and pointing operations may be simultaneously or independently performed thereon.

As used throughout the subject application the term point splitting refers to an operation in which the crosssectional area of the web of a drill is reduced, the foregoing operat'ionreduces the length of the drills chisel edge and provides secondary cutting edges. The term fpointing refers to an operation in which a drill is sharpened or pointed in a conventional manner.

.It is an object of the present invention to disclose structure adapted to be added to or fabricated integrally with a drill pointing machine enabling point splitting operation as well as pointing operations to be simultaneously or independently performed thereon.

Another object is to disclose structure adapted to be added to or fabricated integrally with a drill pointing machine whereby a predetermined relation of a drill mounted in the point splitting structure will be maintained, with respect to an abrasive wheel constituting a component of the pointing machine, throughout a plurality of operations of the machine.

Although the characteristic features of the present invention are particularly pointed out in the appended claims, the invention itself, also the manner in which it may be carried out, will be better understood by referring to the following description taken in connection with the accompanying drawings forming a part of this application and in which:

FIGURE 1 primarily is a schematic plan view of a presently known drill pointing machine embodying a point splitting attachment as disclosed herein.

FIGURE 2 is a fragmentary plan view of the drill pointing machine of FIGURE 1 showing particularly the subject point splitting attachment and the manner of mounting and attaching the latter to the drill pointing machine.

FIGURE 3 is a side elevational view of FIGURE 2.

FIGURES 4 and 5 are fragmentary plan and side elevational views, respectively, showing the relation of a drill with respect to the abrasive wheel of a drill pointing machine during a point splitting operation.

FIGURES 6 and 7 constitute plan and elevational pointing and apoint's'plittin'g operation has been performe United States Patent 0 T.

3,357,138 Patented Dec. 12, 1957 Referring to the drawings, FIGURE 1 shows a machine 10 utilized in effecting a drill pointing operation and to which structure 11 has been added making it possible to perform a drill point splitting'operation thereon as disclosed herein. The machine 10 comprises structure and functions substantially as shown and described in US. Patent No. 3,040,480.

The machine 10 is of conventional construction, accordingly a detailed description thereof is not deemed necessary. Briefly the machine 10 includes a frame 16 having ways 17. Slideably mounted on the ways 1'7 for movement thereon is structure 18 providing bearing means for an abrasive wheel 19. Mounted on and movable with the structure 18 is arm-like structure 20. The structure 20 carried a dressing head 21 embodying a diamond cutting tool (not shown) functioning when actuated to recondition or restore the original contour of the wheel 19 as shown in FIGURES 3 and 5. Movement of the head 21 in fore and aft directions, also toward and away from the wheel '19, occurs on the ways 22 and 23 carried by the arm 24 The machine 10 also includes a head 12 having a fixed relation (in a linear sense) with respect to the frame 16, however, a combined rotating and oscillating movement is imparted to the head 12 as more fully described in the aforementioned patent. It is in the head 12 that a drill is received and rigidly held during a pointing operation as shown in FIGURE 1.

Referring further to FIGURE 1, it will be apparent that certain relationships must be maintained between drills which are to be pointed, in a conventional manner indicated by letter B (FIGURE 6), and the wheel 19 if identically pointed drills are to be provided throughout operations performed by the machine 10. The foregoing is true although the wheel 19 is dressed several times thereby reducing its diameter. A hydraulic system (not shown) and the previously described components of the machine 10 cooperate to maintain the relationships just described in a manner fully discussed in the aforementioned patent. Also, similar relationships must be maintained between a drill the point of which is to be split, identified by the letter B (FIGURE 7), and the wheel 19 if identical point splitting operations are to be performed thereon throughout operations performed by the machine 10 and structure 11.

The structure 11 functions to maintain the relationships just referred to above. The structure 11 includes an armlike structure 14a and adjusting means 15, the structure 14a being fixedly secured to and moves with the structure 18. The structure 14a carries ways 29 adjacent its outer end. Slideably mounted on the ways 29 is a platelike member 28 having a circular aperture provided therein. A projection 27, circular in cross-section, is provided on the base of the means 15 and constitutes an integral part thereof. The adjusting means 15 is mounted on the plate 28, the projection 27 being received in the aperture provided in the plate 28 as shown in FIGURE 3. So mounted, the plate 28, also the means 15, is movable in a linear direction toward and away from the axis of the wheel 19 in response to movements of components of the machine 10 in a manner presently explained.

The adjusting means 15 includes conventional-type manually operable means 32 and 33, respectively, guide holding means 31 and drill holding means 34. The means 31 includes a body portion 30 having an end portion 35, the portion 35 having substantially a right angle relation with respect to the body portion 30. The end portion 35 constitutes a head 36 having a canted surface 39 functioning in a manner that will become apparent as the disclosure progresses. The drill holding ineans 34 consti-t-utes a modified bushing normally having an aperture provided therein, the means 34 normally has a fixed relation in the guide holding means 3 1and is retained'the'r'erespectively,

u in by a set screw 49. Provided in the wall of the means 34 is stud-like drill positioning means 38 which is recieved in one of the flutes of a drill received in the means 34 as shown in FIGURE 5.

It will thus be apparent that a drill positioned in means 34 will be caused to assume certain reiations with respect to the wheel 19, some of these relations are fixed for a particular embodiment and others are adjustable.

For purposes of illustration, it is assumed that a prepointed drill B (FIGURE 6) is positioned in the means 34. Fixed relations of the drill B with respect to the wheel 19, indicated by the Greek letters on and {8 in FIGURES 2 and 5, respectively, are determined by the assembled relation of the various components comprising the means 15 and the latters relation as mounted on the machine 10. The relations a and B are not critical and may vary from installation to installation. Also it will be seen that the relation of the drill holding and drill guiding means 34 and 31, respectively, is such that the drills conical end bottoms on the surface 39 of the head 35 in line contact as indicated by the dashed line 50 in FIGURE 5. Further, the axis of the drill intersects the lower corner of the wheel 19that is, the corner formed by the intersection of the lower and side edges 45 and 49, respectively. Also the relations are such that clearance of approximately one thirty-second l of an inch is provided between the upper surface of the head 36 and the lower surface 45 of the wheel 19.

Regarding the adjustable relations of the drill B with respect to wheel 19; for the most part, the original relationship of an adjustable nature is effected by the operator of the machine or his assistant usually performing the point splitting operation. The locking means 40 is first released allowing rotational and longitudinal movement of the drill holding means 34 in the aperture provided in the means 31. A portion of the drill B, indicated by the numeral 41, is now ground away. Special attention is required during this operation to observe that the following conditions are present at the conclusion of the operation; first, the dr-ills chisel edge 26 must be vertically disposed and second, the drills conical end must be hottomed on the surface 39. The means 40 (set screw) is now utilized to lock the drill guiding means 34 in its fixed relation in the means '31. It will now be apparent that with the drill B repositioned in the means 34, that iswith the positioning means 38 positioned in the other flute of the drill, the diametrically opposite portion 41 of the drill may now be removed (ground away). Thus it will be seen that a drill B (FIGURE 7) is provided having secondary cutting edges, it will also be apparent that once the relations just described are established the points of any number of drills of the same diameter may be split. When the points of drills having different diameters are to be split, drill holding means 34 (bushing) having an aperture of proper size must be substituted for the one previously used.

It will now be apparent that relationships as described above will remain the same until such time as the wheel 19 is dressed or reconditioned, structure maintaining this relationship after a reconditioning operation is maintained by the structure 11. The structure 11 includes a link member 42 pivotally or rockably mounted at its mid-point on the outer end of the structure 14a, this point is referred to as its major pivotal point as indicated by the numeral 43 in FIGURE 2. One end of the member 42 is pivotally secured to the adjusting means 15, also pivotally secured to its other end is an elongated rod member 46. The pivotal points of the member 42 relative to the means and member 46 are referred to as the auxiliary pivotal points of the member 42, indicated by the numerals 44- and 47,

in FIGURE 2. The other end of the rod 46 is pivotally attached to the dressing head 21 as indicated by the numeral 48 in FIGURE 1. Also it will be seen that the respective distances between the major pivotal point 43 and auxiliary pivotal points 44 and 47 are equal.

Also it will be seen that drill pointing operations are effected on the inclined surface 24 of the wheel 19 while point splitting operations are effected on the vertical edge surface 49.

Assuming now that. during the operation of the machine 19 it becomes necessary to dress or recondition the wheel 19. As a result of this operation the diameter of the wheel 19 is reduced a certain amount. For purposes of illustration it is assumed that the diameter of the wheel 19 is reduced an amount 21; (FIGURE 1). Accordingly, if the relation previously described, that is-the relation of a drill (the point of which is being split) with respect to the wheel 19, it becomes apparent that the drill must be moved inboard a distance A or the amount the radius of the wheel 19 is reduced. In elfecting the above mentioned reconditioning of the wheel 19 the dressing head and cutting tool (not shown) necessarily will be moved inboard a distance a.

Inboard movement of the head 21 results in similar movement of the adjusting means 15. The movement of the head 21 is transmitted to pivotal point 47 acting through the rod member 46, this movement in turn is transmitted to the adjusting means 15. In view of the fact that the member 42 is pivotally mounted on fixed structure, the movement just referred to will be transmitted to the means 15 in the opposite direction to movement of the head 21. In other words, means 15 will be moved toward the axis of rotation of the Wheel 19 a distance a or half the amount the wheel 19 is reduced in diameter. Thus it is seen the relationship of a drill, during a point splitting operation, with respect to the wheel 19 is maintained.

In view of the foregoing discussion it will be seen that structure is disclosed making it possible to simultaneously or independently effect pointing and/ or point-splitting op erations on the same machine, that maintains a predetermined relation of a drill and grinding wheel throughout the operating circles of the machine and provides the various other objects of the subject invention.

I claim:

1. In a machine embodying a frame having a head mounted thereon adapted to have drill bits mounted therein while a pointing operation is performed thereon and including structure slideably mounted on the frame, an abrasive wheel and cutting means adapted to recondition the wheel whereby the diameter of the latter is reduced the combination with structure making possible drill point splitting operations to be effected on said machine comprising: track-like means mounted on said slideable structure and extending generally radially of said wheel; adjustable means movably mounted on said track-like means; said adjustable means adapted to receive previously pointed drill bits therein in a predetermined relation with respect to said wheel; and mechanical means adapted to transmit movements of said cutting means to said adjustable means whereby said predetermined relation is maintained during and after a wheel recondition operation.

2. The combination as set forth in claim 1: in which said mechanical means constitutes rod means the ends of which are pivotally attached to said adjusting means and cutting means, respectively.

3. The combination as set forth in claim 1: in which said adjusting means terminates in a head having a chainfered surface and including guide means cooperating to position said pointed bit in said predetermined relation.

4. In a machine embodying a frame having a head mounted thereon adapted to have drill bits mounted therein while a pointing operation is performed thereon and including structure slideably mounted on the frame, an abrasive wheel and cutting means adapted to recondition the wheel thereby the diameter of the latter is reduced the combination with structure making possible drill point splitting operations to be effected on said machine comprising: elongated structure one end of which is fixedly secured to said slideable structure and extending generally radially of said wheel; adjusting means movably mounted on the other end of said el0ngated structure; said adjusting means adapted to receive previously pointed drill bits therein and maintains a predetermined relation thereof with respect to said wheel; and mechanical means adapted to transmit movements of said cutting means to said adjusting means whereby said predetermined relation is maintained during and after a Wheel reconditioning operation.

5. The combination as set forth in claim 4: in which said mechanical means constitutes rod means the ends of which are pivotally attached to said adjusting means and cutting means, respectively.

6. The combination as set forth in claim 4: in which said adjusting means includes guide holding means terminating in a tapered surface and guide means cooperating to position said pointed bit in said predetermined relation.

7. In a machine embodying a frame having a head mounted thereon adapted to have drill bits mounted therein while a pointing operation is performed thereon and including structure slideably mounted on the frame, an abrasive wheel and cutting means adapted to recondition the wheel thereby the diameter of the latter is reduced the combination with structure making possible drill point splitting operations to be effected on said machine comprising: elongated structure one end of which is fixedly secured to said slideable structure and extending generally radially of said wheel; ways on the other end of said elongated structure the center line of which coincides with the axis of said wheel; adjusting means adapted to receive previously pointed drill bits and maintain a predetermined relation thereof with respect to said Wheel; rod means one end of which is pivotally attached to said cutting means; a link member pivotally mounted on said elongated structure at its mid-point; one

end of said link member being pivotally secured to said adjusting means; and the other end of said link member being pivotally secured to the other end of said rod means and functioning to transmit linear movement of said cutting means in one direction equally to said adjusting means in the opposite direction.

8. The combination as set forth in claim 7 in which said adjusting means includes a guide holding means terminating in a canted surface and bushing means the relation of which is such that a previously pointed drill bit will have a specific relation with respect to said wheel at such time as said bit is received in said bushing and the point of said bit is bottomed on said canted surface.

9. The combination as set forth in claim 8: in which said bushing means includes an internal projection adapted to be received in a flute of said bit thereby the latter is caused to assume a specific angular relation with respect to said Wheel at such time as said bit is bottomed on said canted surface.

References Cited UNITED STATES PATENTS 1,865,067 6/1932 Warsaw 51-80 1,993,418 3/1935 Smyser 51219 X 2,388,067 10/ 1945 Markus 5195 2,720,059 10/1955 Shobrook 51-92 3,040,480- 6/1962 Winslow 51-94 3,067,548 12/ 1962 Winslow 51-219 X 3,209,493 10/ 1965 Houser 51-219 X 3,266,194 8/1966 Winslow 51-219 X ROBERT C. RIORDON, Primary Examiner. D. G. KELLY, Assistant Examiner. 

1. IN A MACHINE EMBODYING A FRAME HAVING A HEAD MOUNTED THEREON ADAPTED TO HAVE DRILL BITS MOUNTED THEREIN WHILE A POINTING OPERATION IS PERFORMED THEREON AND INCLUDING STRUCTURE SLIDEABLY MOUNTED ON THE FRAME, AN ABRASIVE WHEEL AND CUTTING MEANS ADAPTED TO RECONDITION THE WHEEL WHEREBY THE DIAMETER OF THE LATTER IS REDUCED THE COMBINATION WITH STRUCTURE MAKING POSSIBLE DRILL POINT SPLITTING OPERATIONS TO BE EFFECTED ON SAID MACHINE COMPRISING: TRACK-LIKE MEANS MOUNTED ON SAID SLIDEABLE STRUCTURE AND EXTENDING GENERALLY RADIALLY OF SAID WHEEL; ADJUSTABLE MEANS MOVABLY MOUNTED ON SAID TRACK-LIKE MEANS; SAID ADJUSTABLE MEANS ADAPTED TO RECEIVE PREVIOUSLY POINTED DRILL BITS THEREIN IN A PREDETERMINED RELATION WITH RESPECT TO SAID WHEEL; AND MECHANICAL MEANS ADAPTED TO TRANSMIT MOVEMENTS OF SAID CUTTING MEANS TO SAID ADJUSTABLE MEANS WHEREBY SAID PREDETERMINED RELATION IS MAINTAINED DURING AND AFTER A WHEEL RECONDITION OPERATION. 